Note: Descriptions are shown in the official language in which they were submitted.
CA 02797744 2012-10-29
WO 2011/137494 PCT/AU2011/000522
1
UNDERCUTTING TOOL
FIELD OF THE INVENTION
The present invention relates to an undercutting tool. In some embodiments,
the
invention is directed to an undercutting tool for producing undercuts in pilot
bores in
concrete, cement, rock and the like, although the scope of the invention is
not
necessarily limited thereto.
BACKGROUND
Undercutting tools are available .in the marketplace and are used to produce
undercuts
in bore walls of concrete and the like.
Existing undercutting tools are complex and usually have a lot of moving parts
to be
able to adequately undercut a bore by forcing the cutting part against the
bore wall.
For example US patent 4,502,554 discloses a rotary power tool for reaming
frusto-
conical undercuts into cylindrical holes by forcing cutting blades outwardly
using a
ram, to undercut the wall of the hole.
A problem with existing undercutting tools is that the time taken to undercut
a hole
can be relatively long, as some of the tools require constant re-adjustment by
an
operator.
In some instances the undercutting tools use off-centre rotation to achieve an
undercut. The problem with these undercutting tools is that they require
specialised
adapters to align the undercutting tool with the bore to be undercut.
Another disadvantage with existing undercutting tools is that the complex
mechanisms used to force the cutting part against the bore wall have to be
disengaged
before the tool can be removed, from the bore hole, which is time consuming
and in
some instances can lead to tools becoming stuck in the bore. Safety is also a
great
concern with existing undercutting tools, with many operators leaving the tool
attached to the drill while the tool is being adjusted. Accidental activation
of the drill
in these circumstances can lead to serious injuries.
RECTIFIED SHEET (RULE 91)
CA 02797744 2012-10-29
WO 2011/137494 PCT/AU2011/000522
2
It is an aim of the invention to provide an undercutting tool which overcomes
or
ameliorates one or more of the disadvantages or problems described above, or
which
at .least provides the consumer. with -a useful choice:
It will be clearly understood that any reference herein to background material
or,
information., or to a prior publication, does not constitute an admission that
any
material, information or publication forms part o:f.the common general
knowledge in
the art, or is otherwise admissible prior art, whether in Australia or in any
other
country.
DESCRIPTION OF THE INVENTION
According to a first embodiment of the invention, there is provided an
undercutting
tool for producing an undercut in a bore, the undercutting tool comprising a
tool body,
which can beat least partially inserted into the bore that is to be undercut,
at least one
wedge moveably. attached to the tool body such that the at least one wedge is
displaced outwardly by centrifugal force when the undercutting tool is
sufficiently.
.rotated, and at least one, cutting surface that. is displaced outwardly as
the at least one
wedge is displaced outwardly and is=adapted to cut into the bore that is. to
be undercut.
Reference to "wedges" herein.: can also refer to one. wedge: Reference to
"cutting
surfaces":herein can also refer to one cutting surface:
In one embodiment, the tool body may 'be adapted to connect to a shaft.
Normally the
tool body will have a threaded' portion to. attach to a corresponding threaded
part on
the shaft. The tool body may be bolted., coupled, fixed, held, locked,
mounted,
secured, welded and/or have any suitable type of attachment means to the
shaft. The
shaft may be attached to a drill, ;cutting machine or the like.
Alternatively;. the tool
body may be adapted to :attach: to a drill, cutting :machine ,or the like. The
tool `body is
normally made of a suitable metallic material: Alternatively the tool: body
may be
30-. made from an alloy, polymer, ceramic, composite an d/or'any material
according to a
suitable .materials selection chart. The tool body may have one or more
connection
points to allow one or mote wedges to be attached to the tool body.
CA 02797744 2012-10-29
WO 2011/137494 PCT/AU2011/000522
3
The tool body is normally substantially cylindrical: in shape. Alternatively
the too].
body may have a shape that. is substantially annular, conical, elliptical,
oval,
rectangular, round, square, triangular, a. polygon in cross section and/or the
like. The
undercutting tool should be able to rotate in the-bore that is to be undercut.
The too]
body is. normally at least partially tubular. Alternatively the . tool body
may be
substantially solid. The tool body may have one or more connection points to
enable
wedges to be attached to the tool body-The connection-points may be holes,
threaded
bores, slots, openings and/or the like in the tool .body.- Alternatively the
connection
points may be arms, .fingers, coupling .members, supports, projections and/or
the like
l 0 on the. tool body
In one etboditiment; the wedges .niay be replaceable. The wedges may be
restricted
from excess pivoting, sliding, bending and/or the like so that the wedges only
extend
to a. desired amount: Normally the wedges are restricted from excess
pivoting,: sliding,
1:5 bending and/or .the like by part of the too] body abutting the wedges
and/or connecting
portions of the. wedges once the wedges have extended the desired amount.
Alternatively the tool body may have projections, that are adapted. to
restrict the
rom excess: pivoting, sliding, bending and/or the like. The projections may be
wedges f
adjustable to adjustthe- amount that the wedges can extend.
The extension of the wedges may also be controlled: by controlling the speed
of
rotation, here the centrifugal .forces -act against the gravitational forces
on the wedges
and the= wedges extend: as the .rotation is increased. Normally, when :the
undercutting.
tool. is not rotating and. in an upright position (i.e. the wedges are: at the
lower end of
25. the tool) and there arc no other forces acting on the wedges, the wedges
will be in a
retracted position due, to the, wedges- being able to pivot, slide,
betd.and/or. the like,
and due to the lack of centrifugal forces biasing the` wedges, outwardly
and/or the
weight of the wedges (i:e gravitational forces biasing the-wedges downwardly),
this
retracted position allows. the undercutting tool to be lowered into a bore.
The wedges
may also be biased into the retracted% position by springs when the tool is
not-rotating,
this may aid insertion o:f the tool into a bore.
CA 02797744 2012-10-29
WO 2011/137494 PCT/AU2011/000522
4
The wedges are normally made of a suitable hard metallic material.
Alternatively the
wedges may be made from an. alloy, polymer, ceramic, composite and/or any
material
according to a suitable materials selection chart.
In one embodiment, the wedges may have one or more connecting portions.. The
one
or more connecting portions on the wedges may be connected to one or more
connection points on the tool body. Normally the connecting portions and
connection
points are connected using, a connecting member such as a. pi.n, split pin,
bolt, cable
clamp, coupling, dowel; hook, keeper; rivet, screw,, fastener and/or the like.
Alternatively the wedges and the tool body can be connected together using a
captive
arrangement, sliding joint, hinge, flexible material; welding and/or the like.
Preferably
once connected, the wedges 'can still move, for example pivot, slide; bend
arid/or the.
like relative to the body. The advantage of having individual wedges is .that
they can
be replaced. The connection points, connecting portions and/or connecting
member
.15 are normally of sufficient size and strength to overcome any forces that
are
encountered;
In another embodiment, the wedges may be integrally formed with the tool body.
The
material of th.e tool body, and the wedges may be flexible enough.to allow the
wedges
.20 to expand. Alternatively; the material between: the wedges and the tool
body may be
sufficiently flexible to. allow the'wedges to expand. The wedges may haw .a
shaped
section. between the wedges.=and:-the ,tool' body which allows the wedges to
expand
whilst still p>: oviding sufficient strength.. The shaped section. between the
wedges and
the tool body-may'be'narrower than the wedges.
In one embodiment, the cutting.. surfaces. may include one' or. more abrasive
pads.
Normally, the cutting surfaces are diamond abrasive pads. The cutting surfaces
may
be`tungste.n pads:': The cutting surfaces may be made from abrasive material
:such .as.
mineral. abrasives, stone abrasives, metal abrasives, natural abrasives,.
synthetic
abrasives, bonded abrasives, coated abrasives and/or the like. Alternatively
the cutting
surfaces may be made from a hardened material such as a metal, alloy,. ceramic
and/or
any material according to a suitable materials selection chart. The cutting
surfaces
may have serrations, projections, sharp edges, work. hardened edges and/or the
like
The cutting surface.may be heat, treated. and/or hardfaced.
CA 02797744 2012-10-29
WO 2011/137494 PCT/AU2011/000522
In, one embodiment, the cutting surfaces may be. attached to the wedges. The
cutting
surfaces may be bonded, brazed, welded, clamped, glued, fastened and/or, the
like on
to the wedges Alternatively the cutting surfaces may be retained by the
wedges.
In another embodiment, the cutting surfaces may be integrally formed as part
of the
wedges. The wedges may be shaped to provide cutting surfaces. The wedges may
be
adapted to be:cutting surfaces. The wedges may be the cutting surfaces. The
wedges
may: be..made from abrasive-mate rialsuch s mineral abrasives, stone.
Abrasives, metal
abrasives, natural abrasives, synthetic abrasives, bonded abrasives, coated
abrasives
and/or the like. Alternatively the wedges mazy be made from a hardened
material such
as a metal, alloy, ceramic and/or any material according to a.. suitable
materials
selection' chart. The wedges may have serrations, projections sharp edges;
work
hardened edges acid/or the like. Th. e.wedges may be heat treated and/or
hardfaced:
.15
In one embodiment, the centrifugal forces acting on the wedges and/or the
cutt.i.ng
surfaces when the undercutting tool: is rotating; displace-the wedges and/or
cutting
surfaces outwardly. An increase. in rotational speed will increase the
centrifugal
forces. Nori ally, the angle between the. wedges and the tool body increases
as the,
wedges. are displaced due'to, increasing centrifugal forces: The angle between
the
wedges and the tool body is normally. close to 0 degrees at .rest.
Alternatively the
angle between the tool body.and the wedges may be closet to 180 degrees at
rest and
the angle between the wedges and the tool body decreases as the wedges are
displaced
due to' increasing 'centrifugal forces Preferably, the undercutting tool is
rotated at'a.
speed to provide sufficient centrifugal force to displace the. wedges
outwardly with
sufficient force to form the undercut. The undercut formed' by the:
undercutting tool
will normally be of a frusto-conical shape due to the manner in which the
wedges
and/or cutting surfaces are displaced outwardly.
The undercutting :tool of the present invention may be used to undercut
materials such
as.concrete, cement, rock, plastics, polymers, ceramics, masonry, wood,
metals, bone;
glass, composites, rubber and/or the like. .
CA 02797744 2012-10-29
WO 2011/137494 PCT/AU2011/000522
6
The, undercutting tool of the present invention may be used with a. drill,
hand drill,
larger drill, larger rig, cutting machine, machining tool and/or the like. The
drill, rig,
machine or the like may be attached .to the structure that is to be cut and/or
may
otherwise be supported to resist the torque created by cutting.
.
The. undercutting tool of the present invention may be of any suitable size.
The
undercutting tool is normally;relativ.ely :large compared to drill bits that
fit a standard
drill, as the centrifugal forces have to be sufficient to cut the material to
be undercut.
However, = the undercutting tool may : also be of. a. smaller size, in this
case, the
1.0 rotational speed of the undercutting :tool may need to, be increased to
provide
sufficient centrifugal force:.
The undercutting tool of thepresent invention may be controlled using any
suitable
control method to adjust the speed -of rotation of the. undercutting tool in
order to
control the angle of the wedges and/or the centrifugal force.
Some benefits of the undercutting tool of the present it vention,include.the
following:
1 Reduced. -costs;
2. Durability;
3. .Less. moving parts;
4. Construction simplification;
5. Ease of assembly;
6.. Safer operation; -and
7. Ability y to operate. under most conditions.
:.
BRIEF DESCRIPTION OF THE DRAWINGS
One or -more preferred embodiments of the invention will now be described, by
way
o:f.example only,:with referenee.to the accompanying drawings in which:
Figure i is a view of an undercutting tool.
Figure '2 is a view of an undercutting tool connected to-a shaft.
Figure 3 is. a view of an. undercutting tool with wedges in a retracted
position.
Figure 4 is an underneath view of an undercutting tool.
Figure 5 is a view of an undercutting tool with. wedges in a displaced
position,
Figure 6 is a view of a shaft adapted to attach to the, undercutting tool.
CA 02797744 2012-10-29
WO 2011/137494 PCT/AU2011/000522
7
BEST MODE
With reference to Figure 1,;.there is shown an undercutting tool 10 having a.
tool body
12 and connected'to six wedges 12. The connection points 1.4 on the tool body
12 are
attached to the connecting portions 28 of the wedges 12 by connecting members
16.
The connecting members 16 are slightly deformed at the ends to prevent them
from
coming lose from the connection points 14. Cutting surfaces 26- are attached
to the
wedges 12.
Figure 2 shows an undercutting: tool' 10. attached to a shaft 20. as the
undercutting tool
10 rotates, the wedges 24 are forced outward increasing, the. angle 30 between
the, tool
body 12 and the wedges 24. The angle 30 of the: wedges 24 as shown in figure 2
would be equivalent to a medium rotational speed of 'the undercutting tool..
Normally
the undercutting tool 10 would be attached to a drill or the like.(not shown)
and
lowered into a bore .(not shown), the wedges 24 would be in a contracted
position
allowing the undercutting:to- of 10 to be lowered. into the bore. Once in,
position, the
undercutting cool 10 would. be rotated, causing : the. wedges.: 24 to be
displaced
outwardly due to the centrifugal forces, causing the cutting surfaces 26 to
cut. into the
wall of the bore (not shown) 'Elie speed of the undercutting tool would be
controlled
to ensure. that the wedges.24 are displaced outwardly to a: suffcient angle.
After the
bore has been undercut, the wedges 24 will be at. a' desired angle and..
rotating freely.
Once the undercutting tool has stopped rotating, the wedges will be in the
retracted
position and the tool can be `removed from the undercut bore. The wedges 24
are
normally at: an angle. close to 0 degrees at rest, this angle- then increases
as the
undercutting tool. 10 is rotated..
Figure 3 shows an undercutting tool 10 with. a threaded portion 18, The
threaded
portion 18 enables the undercutting. tool: to be attached to a shaft '20 (as
shown in
figure 6) which has a corresponding threaded bore 22 .(as shown in figure 6).:
The
wedges 24'are in a partially retracted position.
.30
Figure 4 ,shows an undercutting tool 10 with wedges 24 pivotably.attached to
the .tool
body .12. The connecting portions 28 of the wedges 24 are attached to the
connection
points 14 of the tool. body 12 by connecting members 16.
CA 02797744 2012-10-29
WO 2011/137494 PCT/AU2011/000522
8
Figure 5 shows an undercutting tool 10 with cutting surfaces welded onto the
wedges
24. The wedges 24 which are pivotably attached to the tool body 12. The wedges
24
are in an outwardly displaced position.
The. foregoing embodiments are illustrative only of the principles of the
invention, and
various modifications and changes will readily occur to those skilled in the
art. The
invention is capable of being practiced and carried out in various ways and in
other
embodiments. It is also to be understood that the terminology employed herein
is for
the purpose of description and should not be regarded as limiting.
In. the present specification anad., claims (if any), the word "comprising"
and its
derivatives including "comprises". and ".comprise" include .each of the stated
integers
but does not exclude the inclusion of one or more further integers.
Reference throughout this specification to one embodiment' .6T "an embodiment
"
.means that -a particular feature, structure, -or characteristic described, in
connection
with the embodiment .is `included in at least one embodiment of the present
invention.
Thus, the appearance of the phrases "in one embodiment" or "in an embodiment"
in
various places throughout this specification are not necessarily all.
referring to the.
same 'embodiment Furthermore, the particular: features, structures, or
characteristics
may be combined in an.. suitable Ananner in one or. more combinations. .
In, compliance with the statute, the invention has been described in language
more or
_less specific to structural or. methodical features. It its to be understood
that the
invention is not. limited to specific features shown or described since the
means herein
described. comprises preferred forms of putting the invention into effect. The
invention is, therefore, claimed in any of its forms or, modifications within
the proper
scope of the.appended claims (if any) :appropriately interpreted by those
skilled in the
art. S
